Gravity concentrator for ores



Dec. 21,1926. v 1,611,339

- F. H. COTHAY GRAVITY CONGENTRATOR FOR ORES Filed AugusfI 18 1924 Fu Il 1 um... A

ytered hcwevcr in that the bed ten= Vconsolidated so that tin-stone cannot properly sink into it, but passes over the ritlles and Patentes Dec. 21, 1926.

narran srarss artnr .erica FRANK HERNAIWAN COTHAY, F SUSSEX, ENGLAN), ASSIGNOR OF ONE-HALF T0 ROPE? TIN LIIVTEQD, OF LGNDON, C. 2. ENGLAND, A BRTISH COMAN'Y.

GRAVTY CONCENTRATOR FOR GRES.

Application led August l, 1924, Serial No.

treatment of allnviuni-containing values in' the term ol: tin-s'ioneand comprising an inclined rectangular sluice or trough provided at intervals ot every 1"'cw feet with cross rilitles. The alluvium collects behind the rittles to a depth equal to the height ot the rittle, which may be several inches, while a stream ot spoil or pulp is flowing through the sluice. rfin-stone out of the pulp sinks into thel bed of material while the lighter materials pass over. Diticulty is encoun- 3 to beeoi'ne on down the sluice. Attempts to `prevent this by raking are only partially successful. The prongs ot rakes aliect the material only along certain lines and cause channels, particularly it they are mechanically worked. Hand shovels can be used but it is desirable to have a mechanical device which will secure continuous and uniform agitaion.

According to the present invention there 'is provided in a gravity concentrator, the

combination of an inclined concentrating sluice, rili'les therein extending yacross the sluice, agitating elements which are ot less depth than the ritlles and which extend across the sluice close to the bottom thereof between the ritlles, and means to reciprocate the agitating elements along the sluice so that material collected in the pockets formed by the ritlles is prevented from compacting without being stirred up.

The agitator may consist ol a band et segmental cross-section, the fiat face ol the band being lower-most.

The action or the agitator is to disturb the material gently lto prevent it caking and to allow the heavier tin-stone to settle through it. The superincun'ibent stratum ot material. above the wire is gently pulsated throughout its substance and kept uniformly loose, so that it affords an easy entry lor the heavier values.

The accompanying drawing illustrates by way of example one form ot concentrator embodying the invention. In the drawing- Figure l is a vertical longitudinal section through the apparatus.

Figure 2 is a vertical. transverse section therethrough and about 18 inches,

-S and in Great 4tay 14, 1924.

`Figure 3 is a cross-section ot a certain part ot the apparatus7 shown on a larger scale than 'that et theother figures.

Like re-terence characters indicate like parts in the various figures.

The appar tus comprises several (preterably three or four) sluices l, arranged side by side. These are made ot sheet metal and are ol considerable size. They may be about 100 feet long. The sluices are moreover provided with cross-riiiles 2 at intervals ot, say, every 8 feet, and they are set at a slight slope by being mounted in a pivoted cradle (not shown), the inclination ot' which can be suitably adjusted.

ln each slnice is a series of agitating trames. rlhcsc comprise longitudinal members 3 to w ich are secured cross-members 4 o'l' fiat steel bar which are bent downwardly at their ends. The bottom ends of the cross-` members l nearly touch thebottom of the trough and between the two ends of each of them is stretched tightly a steel wire which is segmental in cross-section, being flat on its undertace and rounded at its upper tace, so that the general section ot the wire is elongated in the direction ot the length ol the sluice. rthis wire constitutes what-is sometimes referred to in this specification as the agitator ot the apparatus. The thickness ot the wire may be about one quarter of an inch, `and the breadth, say, about one inch. The wires 5 are ont a suliicient length to extend completely across the trough l and the bent-down ends ot the steel members 4 which carry them lie close to the sides of the trough so as not to interfere with the bed ot material 6 which collects therein, The bentdown ends of the cross-members l are ot such a depth that the cross-members and thelongitudinals 8 which carry them are clear ot the material 6 within the trough.

The frames are reciprocated slowly, say,

at l0 or 15 double strokes a minute and the length' of the stroke, which may be. say, is so related to the distance between adjacent wires that the whole surface of thevtrough is traversed by the wires, The frames are supported .from an overhead structure 7 by rigid links 8, which may, if desired, be adjustable in lengt-h.

Mechanism for reciprocating the frame may comprise at each side, a crank 9, rotatable at the required rate, about an axis disposed transverse to the frame.v The pin of loo this crank may be connected, by a simple system of links and cranks 10, to a pivotal connection to the longitudinal member 3 of the frame, the said system of cranks and links being such that rotation of the crank 9 will occasion reciprocation of the frame, with the required stroke.

ln operation the pulp or slurry of alluvium is directed into the troughs l, flows therethrough by gravity and deposits a bed of alluviuin in each trough against the rifties. This ced of alluvium overlies the agitating wires and is prevented from ealing by the reciprocation of the wires which,

while not disturbing the material unduly, yet keeps itall loose, so that the heavier valuable particles may sink into and through the bed, while the lighter gangue particles are washed away.

The apparatus may be mounted upon a dredging barge so that alluvium recovered from the bed of a river may be delivered directly into it.

In the case where the discharge end of a sluice is on land.` or otherwise accessible, the discharge itself may be arranged to operate a water-wheel or equivalent motor which supplies the power to operate the agitator.

Various modifications can be made to the apparatus, as. will lbe obvious, without departing from the spirit or scope of the invention. For instance the frame may take a form other than that particularly described, and the cross-section of the agitator wire may be other than segmental, although a segmental cross-section is preferable, in that it tends more effectively to loosen the bed of material than some other sections of wire.

that l claim as my invention and desire to secure by Letters Patent is l. ln a gravity concentrator the Vcombination of a stationary inclined concentrating sluice, riffles therein extending across the sluice so as to cause the material to collect as an immersed bed therein, agitating elements which are shallow as compared with the depth of the ritlies and are so positioned within the sluice in close proximity to the bottom thereof as to extend transversely across the sluice and be embedded in a'lowcr stratum only of the immersed bed of matcrial between the rili'les, and operating means for the agitating elements whereby the latter mayY be `gently reciprocated transversely to their length in the plane of said lower stratum so as to maintain the bed of material loose throughout without having a stirring up effect on the material and without forming channels on the upper surface thereof, substantially as and for the purpose described.

2. In a gravity concentrator the combination of a stationary inclined concentrating sluice, rifi'les therein extending across the sluiceso to cause the material to collect as an immersed bed therein, agitating elements which are shallow as compared with the depth of the rillies and are comprised of bands ot substantially segmental cross-sec tion disposed with the flat face lowermost, the said agitating elements being positioned within the sluice in close proximity to the bottom thereof and extending transversely across the sluice, being embedded in a lower stratum only of the immersed bed of material between the ritlles, and operating means for the agitating` elements whereby the latter may be gently reciproeated transversely to their length in the plane of said lower stratum so as to maintain the bed of material lose throughout without having a stirring up effect on the material and without formingl channels on the upper surface thereof, substantially as and for the purpose described.

3. In a gravity concentrator for material carried in liquid suspension, the combination of a stationary inclined sluice along which a pulp of the material to be concentrated liows, a plurality of riftles extending across the sluice at spaced intervals,`

thereby causing the material to collect as immersed masses deepening from one end to the other, a plurality of agitating elements extending transversely across the sluice between adjacent riflles, said agitating elements being positioned in close proximity to the bottom of the sluice and being` shallow as compared with the depth of the rifl'les, whereby they are effective for agitating only the Vlowermost stratum of the immersed masses between the ritties, and operating means for the agitating elements, said means being effective for gently reciprocating the agitating elements in the plane of said lower stratum and in a direction Vsubstantially parallel to the direction of 

